EP 2372638 A1 20111005 - A black and white stretch method for dynamic range extension
Title (en)
A black and white stretch method for dynamic range extension
Title (de)
Schwarz-Weiss-Spannverfahren zur dynamischen Bereichserweiterung
Title (fr)
Procédé d'étirement en noir et blanc pour extension de plage dynamique
Publication
Application
Priority
TR 201001660 A 20100304
Abstract (en)
Input content for TV receivers commonly has narrow dynamic range; lack of pure dark or lack of pure bright pixels. This situation makes user to feel low contrast for an image on screen. Thus, narrow dynamic range should be extended. For this purpose present invention describes a method for black and white stretch (BWS) of intensity values to increase dynamic range of input video signal. Said method describes a BWS algorithm which has the following steps; detection of the dynamic range of the frame histogram by finding the minimum and maximum existent intensity values, calculation of the median value to determine the starting stretch levels, calculation of the stretch strength according to the histogram distribution for both black and white region dependently and update of the histogram mapping function with the new terms within the stretch boundaries by a specific mapping curve. After above steps, to eliminate sharp increase or decrease, the map is smoothed by a high-order-low-pass filter without changing the end points. Finally, the determined mapping function is weighted with the previous frames' mapping function in order to remove possible flickering effect due to small changes in consecutive frames.
IPC 8 full level
CPC (source: EP)
G06T 5/40 (2013.01); G06T 5/92 (2024.01); G06T 2207/10016 (2013.01)
Citation (applicant)
- GB 2425670 A 20061101 - HITACHI LTD [JP]
- US 2006239581 A1 20061026 - NEUMAN DARREN [US]
- US 6148103 A 20001114 - NENONEN PETRI [FI]
- US 6782137 B1 20040824 - AVINASH GOPAL B [US]
Citation (search report)
- [Y] US 2005031200 A1 20050210 - LEE SANG-SOO [KR], et al
- [YD] US 2006239581 A1 20061026 - NEUMAN DARREN [US]
- [Y] WO 2008149363 A2 20081211 - DBLUR TECHNOLOGIES LTD [IL], et al
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated extension state (EPC)
BA ME
DOCDB simple family (publication)
EP 2372638 A1 20111005; EP 2372638 B1 20121107; ES 2399195 T3 20130326; TR 201001660 A2 20110921
DOCDB simple family (application)
EP 11156605 A 20110302; ES 11156605 T 20110302; TR 201001660 A 20100304